Effects Of Deep Ripping Research Articles

Deep blade loosening increases root growth, organic carbon, aeration, drainage, lateral infiltration and productivity

All cultivated soils are prone to rapid reconsolidation when wet, particularly structurally unstable soils. This predisposes them to waterlogging, slow and limited infiltration, rapid drying, and poor establishment, growth and production of crops. Field-scale research was undertaken to develop soil management and/or engineering practices that will maintain a stable, loose tilth with aeration, drainage and infiltration properties that prevent waterlogging, enhance infiltration and increase crop production.The effects of deep ripping plus gypsum, permanent raised beds (PRB), deep blade loosening at 250 mm depth (DBL) and no-tillage crop establishment (NT) were studied in controlled traffic regimes on rainfed and irrigated crops. The DBL treatment severs roots at about 250 mm depth and loosens without inverting the overburden. Experiments were undertaken from 1997 to 2011 on winter waterlog-prone unstable sandy loam over clay soils in Western Australia, on an unstable fine sandy clay loam in Pakistan and on a self-mulching clay in Queensland. All sites were operated on a field scale as part of the commercial operations of collaborating farmers. Root zone soil conditions were monitored with measurements (0–400 mm) of bulk density, tilth porosity, hydraulic conductivity, perched water table depth, root mass, organic carbon, total nitrogen and moisture profiles. Irrigation applications and crop yield were also recorded.Bulk density data on all experimental sites showed reconsolidation of the tilth created by deep ripping with or without gypsum in the NT treatment occurred substantially within one growing season. The reconsolidated NT treatment in Western Australia also had low hydraulic conductivity, air-filled porosity values of only two to 4% at a soil moisture potential of −250 mm (PRB height) and suffered long duration waterlogging events. The DBL-PRB treatment on these soils remained largely unconsolidated, had larger hydraulic conductivity, an air-filled porosity at −250 mm moisture potential of ≥10%, and did not suffer waterlogging. Modelling using drainage theory showed that DBL-PRB could be as wide as three metres and easily drain saturated beds within two days, thus precluding waterlogging.Root mass in the 0–400 mm in DBL-PRB treatment was, on average, seasonally 31% greater than the NT treatment. This increase in root mass is shown to have produced increases of 48% in soil organic carbon and 34% in total soil nitrogen content, and, over 19 cropping seasons with six different types of crop, the DBL-PRB treatment produced an annual average increase in grain yield of 23% over that of the NT treatment.The DBL-PRB treatment also substantially increased the amount and rate of lateral infiltration. Irrigation wetting fronts were both measured and predicted by infiltration theory to reach the centre of 2 m wide DBL-PRB in one third to one half of the time taken in NT-PRB.DBL practice has the potential to stabilise a deepened tilth in all soil types through the conservation of the structure and mass of enhanced root growth, which increases soil organic carbon, total soil nitrogen and crop productivity, as well as preventing waterlogging and improving irrigation efficiency.

Effects of deep ripping and organic matter amendments on Ap horizons of soil reconstructed after coal strip-mining

Deep ripping is a common management technique used to shatter dense subsurface soil horizons that limit percolation of water and penetration of roots. Most studies have concentrated on the effects of deep ripping on subsoils, with few examining the effects on surface soil horizons. A study was conducted on reclaimed fields (undisturbed soil Albic Luvisol) at the Highvale coal mine approximately 80 km west of Edmonton, Alberta, Canada, with objectives to evaluate the effect of deep ripping, with and without the use of organic matter amendments, on the physical and chemical properties of Ap horizons of reconstructed minesoils. Significant treatment effects were identified for particle size distribution (all fractions), plasticity index and the October mean penetration resistance (PR), but effects on bulk density, soil water content at the time of sampling, water retention characteristics and modulus of rupture were non-significant. Soil chemical properties significantly affected included pH, soluble Ca and Mg, exchangeable Na and K, exchangeable Ca:Na ratio and loss of ignition. Addition of subsoil to the Ap horizon as a result of deep ripping likely caused the changes. They are expected to make the seedbed more difficult to cultivate and manage unless specific management practices such as organic matter additions are adopted to overcome the detrimental changes in soil properties that have occurred. Key words: Manure, peat, reclamation, soil properties, subsoiling, surface horizon, tilth

Management of excess water in duplex soils

Excess water in duplex soils can be removed by drains. In soils in which drainage is impractical, some success has been obtained by deep ripping and by gypsum amendment. These practices can increase profile storage or drainage. Interceptor drains are suitable for duplex soils with slopes of more than about 1.5%. On more gentle slopes, relief drains are used to remove excess water. Subsurface tube and mole drains have been used successfully to drain cereal crops in Victoria, but in Western Australia open drains are preferred because they can carry storm runoff as well as seepage waters. The greatest cost of open drains is the land removed from production. Over 35% of the rain falling during the growing season has been removed by drains in Victoria and Western Australia in wet years. Drainage was almost entirely downslope of monitored interceptor drains in Western Australia, which is not predicted from the theory. Simulation of water levels between drains and of drain flows using the DRAINMOD model indicated significant, preferred pathways for water flow to drains. The pathways explain the predominantly downslope effect of interceptor drains and the wide drain spacings which can be used. Deep ripping and the incorporation of gypsum can reduce waterlogging in some soils, but has had no effect in several others. The effect of deep ripping on recharge is unclear. Drains may decrease groundwater recharge, water and wind erosion, and soil structure decline. Their effect on phosphate export from catchments is unclear.

Soil water deficits, water use, and the water balance. Comment on 'Effects of deep ripping and liming on soil water deficits, sorptivity and penetrometer resistance', by G.R. Steed, T.G. Reeves and S.T. Willatt (Aust. J. Exp. Agric., 1987, 27, 701-5)

Soil water deficits, water use, and the water balance. Comment on 'Effects of deep ripping and liming on soil water deficits, sorptivity and penetrometer resistance', by G.R. Steed, T.G. Reeves and S.T. Willatt (Aust. J. Exp. Agric., 1987, 27, 701-5)

Effects of deep ripping on chemical and physical properties of a solonetzic soil in East-Central Alberta

The effects of deep ripping using 2 shank spacings (56 and 112 cm), single moldboard plowing and normal shallow tillage on soil chemical properties were compared at 2 sites near Halkirk, Alberta (Canada). Electrical conductivity (EC), Sodium adsorption ratio (SAR) and pH were compared. In addition the influence of deep ripping on moisture distribution and particle size distribution in the profile were determined. Single moldboard deep plowing resulted in substantial changes to soil chemical properties throughout the profile, whereas deep ripping with a 56-cm shank spacing caused little or no changes. Deep ripping with a 112-cm shank spacing induced significant changes in SAR and pH in the upper 2 horizons of the area immediately affected by the shank. The soil was moist when the field with a 56-cm spacing was ripped, and very dry a year later when the field with a 112-cm spacing was ripped, making it difficult to evaluate the effect of shank spacing. Maximum shattering occurred when the soil was dry. Deep ripping with a 112-cm shank spacing significantly increased moisture penetration in the area immediately affected by the shank and in areas adjacent to the shank (20-cm over). Also, deep ripping with a 112-cm shank spacing lifted clay upwards in the profile, and increased SAR in the upper part of the profile.

Effects of deep ripping and liming on soil water deficits, sorptivity and penetrometer resistance

A field experiment was conducted at Rutherglen, in north-eastern Victoria, to determine the effects of liming and deep ripping on soil water extraction by wheat, sorptivity of water into the soil profile and soil resistance to a penetrometer. The site was typical of many cropping paddocks in the region. In the unmodified state the top 20 cm of the soil profile was acid (pH 4.80) and there was a dense hardpan between 7.5 and 17.5 cm depth. Deep ripping increased water extraction by wheat by an average of 8 mm during a drought season (1982), but had no effect on water use in a wet season (1983). The major effect of ripping was to increase the water use in winter from below the ripped zone (40 cm) compared with the unripped treatment. Lime, either with or without ripping, had no significant effect on crop water extraction. Sorptivity, a measure of infiltration, was increased by ripping alone and by ripping plus lime. Soil resistance to a penetrometer was reduced by deep ripping; an effect which had persisted at least 30 months after the last ripping operation. Economic wheat yield responses were obtained by using deep ripping and liming to improve soil physical properties at this site.

The size and horizon of origin of fragments produced by deep ripping texture contrast soils

Two texture contrast soils were cultivated by deep ripping when they were drier than their lower plastic limits. The size distribution and soil horizon-of-origin of the resulting fragments were measured. One soil, a transitional red-brown earth, had either been previously uncultivated below the A horizon or had been deep ploughed and gypsum added two years previously. There was much fragmentation and mixing of soil from both of the horizons. Fine soil (<2 mm diam.) from the A horizon reached the lower depths of the trough made by the ripping and coarse soil from the B horizon (>50 mm) was brought to near the surface. The fragment size distributions were characteristically bimodal. Fragments of the fine mode (<2 mm) came mainly from the A horizon, fragments of the coarse mode (11-25 mm or larger) came mainly from the B horizon. In the laboratory, clods from the deep ripped soil were crushed at the same low water potential (air dry). The crushing energy per unit mass (specific crushing energy) was inversely proportional to the normalized geometric mean diameter of the fragments produced. Suggestions are made for modelling the effects of deep ripping.

Effects of deep ripping, direct drilling, gypsum and lime on soils, wheat growth and yield

In northeast Victoria, wheat crops often have patches of stunted and chlorotic growth which result in overall yield depressions of about 25%. Root defects are common in the stunted patches, and are associated with subsoil hard-pans and acid soils. In 1981, two experiments were commenced aimed at alleviating the soil physical and chemical problems. Treatments involved gypsum applications (0 and 5 t ha −1) and deep ripping (0-, 20- and 40-cm depths), followed by either cultivation or direct drilling of wheat for 3 years. In 1982, the experiments were split and lime (0 and 2.5 t ha −1) was applied as a main treatment. In 1981, deep ripping increased wheat root and top growth during winter, while gypsum depressed growth. On one experiment, waterlogging subsequently resulted in crop loss; on the other experiment grain yields showed an increase of 0.3 t ha −1 after deep ripping to 40 cm depth, and a reduction of 0.3 t ha −1 due to gypsum. In 1982, drought and frost reduced yields, and treatments had little effect on wheat yields. Penetrometer testing showed that ripped soils were still loose on one site, but on a red duplex soil, the subsoil had partially re-compacted, especially under traffic. Where soil was ripped then direct drilled, gypsum had a marked effect in reducing penetrometer resistance, and this effect was still evident in the final year. In 1983, cultivation and traffic increased penetrometer resistance while direct drilling maintained a lower resistance in loosened subsoils. Direct drilling gave yields equivalent to those with cultivation. An initial deleterious effect of gypsum on wheat growth was reversed later in the season, and a combination of lime, deep ripping and gypsum gave the highest yields at both sites. Deep ripping and liming on strongly acid and compacted yellow duplex soils give considerably improved yields for wheat. On red duplex soils, however, the longevity of the effect of deep loosening is still in question, and use of gypsum requires further research.

Effect of deep ripping, the previous crop, and applied nitrogen on the growth and yield of a wheat crop

The response, to ripping and nitrogen application, of a wheat crop which has grown after a 1 -year crop of wheat, lupins and pasture was measured in terms of tops growth, nitrogen uptake, rooting depth and grain yield. Although there were limitations to the data set used, a graphical method demonstrating separation of the effects of treatment on soil nitrogen status and nitrogen use efficiency was compared using the classical analysis of variance. Ripping increased the rate of root extension and this caused the more efficient use of fertiliser nitrogen early in the season. Compensatory nitrogen uptake took place late in the season on the unripped plots. However, grain and tops yields were significantly greater on the ripped plots. The major effect of a previous crop of lupins was to increase the nitrogen status of the plots, although early in the season the efficiency of nitrogen use was also improved. A dry finish to the season turned a statistically non-significant ripping x nitrogen x species interaction for tops growth into a significant negative interaction for grain yield.